Hi all,

Our company has been recently engaged to provide LEED energy
modeling services for an addition to an existing high school which is approx.
30 years old. The new addition is being targeted for LEED gold certification. I
have previously performed LEED energy modeling services for a new university
building which is targeting LEED gold also. My question is, how does an
addition differ from an entirely new build? I assume that you still have to
model the existing building systems complete with the new mechanical system for
the extension and compare it against the baseline just like a new build?

Also, the high school is looking at overhauling the existing
mechanical system which is a conventional chiller/boiler system. There are two
options:

1) Replace
the existing chiller (30 years old and inadequately sized for the new
extension) with a new chiller in line with current standards and sized to meet
the new additional loads.

2) Install
a geo-thermal system with back up provided by the conventional system.

We are responsible for the feasibility study of Option 1. I
have already constructed the energy model using IES and we are waiting back
from the other consultant with their results from the geo-thermal study. Both results will go to the school board and they will have the final say as to what system is going to be installed. My
final questions are:

1) If
it does end up that the geo-thermal option is the more cost effective option
and is chosen by the school board ? what baseline system do you choose to model
this? The school has a floor area of approx. 250,000 square feet with two
levels above ground and a basement.

2) Has
anyone done a geo-thermal model using IES? Since I have the model built already
through the feasibility study, I don?t want to have to build another model
using a different program.

I would greatly appreciate any advice as I am still pretty
inexperienced when it comes to LEED modeling.

Thanks

Donal